Cows produce milk for the same reason that humans do—to nourish their young—but calves born on dairy farms are taken from their mothers when they are just one day old and fed milk replacers so that humans can have the milk instead.

In order to keep a steady supply of milk, the cows are repeatedly impregnated. Several times a day, dairy cows are hooked by their udders to electronic milking machines that can cause the cows to suffer electrical shocks, painful lesions, and mastitis.

Some spend their entire lives standing on concrete floors; others are crammed into massive mud lots.

Cows have a natural lifespan of about 25 years and can produce milk for eight or nine years, but the stress caused by factory farm conditions leads to disease, lameness, and reproductive problems that render cows worthless to the dairy industry by the time they are four or five years old, at which time they are sent to the slaughterhouse.